JP6390002B2 - Imaging device - Google Patents

Description

  The present disclosure relates to an imaging apparatus including a camera shake correction system with a built-in body and an electronic front curtain reset.

  In recent years, in a single-lens type digital camera, an electronic front curtain that uses an electronic control front curtain (hereinafter referred to as an electronic front curtain reset) on an image sensor and a mechanical shutter rear curtain (hereinafter referred to as a mechanical rear curtain) in combination. A curtain shutter (hereinafter referred to as an electronic front curtain shutter) is used (see, for example, Patent Document 1).

  In addition, in the electronic front curtain shutter, a configuration is disclosed in which reset scanning is performed for each line to reset the accumulated charge amount of the pixels of the image sensor to zero by resetting the electronic front curtain prior to the running of the mechanical rear curtain. (For example, refer to Patent Document 2). In this way, after a predetermined time, the mechanical rear curtain is operated to shield the light, and scanning is performed for reading out a signal after a predetermined time elapses for each line of the image sensor, thereby realizing an imaging operation.

  The electronic front curtain shutter can improve the camera performance by downsizing the imaging device, shortening the release time lag, reducing the noise, reducing the release shock, and the like.

  In addition, many single-lens digital cameras have a camera shake correction function. A camera shake correction system built in the camera body (hereinafter referred to as camera shake correction in the body), and camera shake correction in the lens. There is an image stabilization system with a built-in lens.

  In-body camera shake correction can correct camera shake generated in the camera body by moving the image sensor. In addition, the camera shake correction in the body can also correct the rotational shake by rotating the image sensor.

JP 2010-41510 A JP 2012-129588 A

  When the shutter speed of the camera is set to a high-speed shutter, the slit width between the front curtain and the rear curtain must be narrowed and controlled, so high accuracy is required for shutter control. For example, in order to realize a high shutter speed of 1/4000 or more, a high accuracy with a positional error between the front curtain and the rear curtain of the order of 0.1 mm is required. If this accuracy is not satisfied, the target shutter speed cannot be obtained, or exposure on the image is not uniform.

  When the electronic front curtain shutter is used, more severe control is required than when the mechanical front curtain-mechanical rear curtain shutter is used. Specifically, it is necessary to control the timing and locus of electronic front curtain reset after accurately grasping the position and locus of the mechanical rear curtain.

  However, when the camera shake correction in the body and the electronic front curtain shutter are used together, the timing of the electronic front curtain reset with respect to the mechanical rear curtain may shift because the position of the image sensor changes by correcting the generated camera shake. Shutter speed cannot be obtained, and uneven exposure occurs.

  In order to correct this, Patent Document 2 discloses a configuration for correcting the reset timing of the electronic front curtain reset according to the position of the image sensor.

  However, when the rotation direction can be corrected by the in-body shake correction, the control cannot be performed only by correcting the reset timing in the vertical direction.

  In addition, since incident light from the lens reaches the image sensor with an incident angle, shading and vignetting may occur at the top and bottom of the image if the electronic front curtain reset is started at a position where the image sensor deviates from the initial position. It becomes.

  The present disclosure provides an imaging apparatus that corrects exposure unevenness that occurs when in-body camera shake correction and electronic front curtain reset are used in combination.

  An imaging apparatus according to the present disclosure includes a camera shake detection unit that detects camera shake, an image sensor that captures a subject image, a camera shake correction unit that moves the image sensor in a plane perpendicular to the optical axis, and an accumulated charge amount of the image sensor. An electronic front curtain that performs a reset operation, a mechanical shutter that switches between shielding or passing of a subject image condensed on the image sensor, and a camera shake control unit that generates a camera shake correction signal and controls the camera shake correction unit from the camera shake detected by the camera shake detection unit And comprising. When receiving a shooting instruction, the camera shake control unit moves the image sensor to a predetermined position and then controls the electronic front curtain to operate.

  The imaging apparatus according to the present disclosure can suppress the occurrence of uneven exposure when the in-body camera shake correction and the electronic front curtain shutter are used in combination.

1 is an external view of a digital camera according to Embodiment 1. FIG. FIG. 2 is a rear view of the digital camera according to the first embodiment. FIG. 3 is a configuration diagram of the digital camera according to the first embodiment. FIG. 4 is a timing chart showing the operation of the camera controller in the first embodiment. FIG. 5 is a flowchart showing exposure control of the camera controller in the first embodiment. FIG. 6 is a schematic diagram of a camera shake correction unit and a CMOS image sensor according to the first embodiment. FIG. 7 is a 7-7 direction view of the camera shake correction unit 132 of FIG. 8 is an 8-8 direction view of the camera shake correction unit 132 of FIG. FIG. 9 is a diagram illustrating a movable range of the camera shake correction unit according to the first embodiment. FIG. 10 is a diagram illustrating an example of trajectory curves of the electronic front curtain and the mechanical rear curtain. FIG. 11 is a diagram showing another example of trajectory curves of the electronic front curtain and the mechanical rear curtain. FIG. 12 is a diagram for explaining the photographing operation when the CMOS image sensor is in the initial position. FIG. 13 is a diagram for explaining the photographing operation when the CMOS image sensor is not in the initial position. FIG. 14 is a flowchart showing the photographing operation in the first embodiment. FIG. 15 is a diagram for explaining the measurement of uneven exposure at the top and bottom of the CMOS image sensor.

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, Embodiment 1 will be described with reference to FIGS.
[1. Constitution]
[1-1. Configuration of digital camera]
FIG. 1 is an external view of a digital camera 100 according to the first embodiment.

  The digital camera 100 includes an interchangeable lens 101 and a camera body 102 to which the interchangeable lens 101 can be attached. The camera body 102 includes a release button 103. When the camera body 102 receives a half-press operation by the user of the release button 103, the camera body 102 transmits a control signal to the interchangeable lens 101 so as to perform an autofocus operation. In addition, when the camera body 102 receives a full pressing operation by the user of the release button 103, the camera body 102 performs a photographing operation of a subject image formed through the interchangeable lens 101.

  FIG. 2 is a rear view of the digital camera 100 according to the first embodiment. On the back side of the digital camera 100, the camera body 102 includes a camera side operation unit 107 including a touch panel 104, a center button 105, and a cross button 106. The camera body 102 receives an operation by a user from the touch panel 104 or the camera side operation unit 107 and performs control corresponding to the operation content.

  FIG. 3 is a configuration diagram of the digital camera 100 according to the first embodiment.

  The interchangeable lens 101 includes an optical system including a lens controller 108, a lens mount 109, a focus lens 110, and a zoom lens 111, a focus lens driving unit 112, a focus ring 113, a zoom lens driving unit 114, a zoom ring 115, a diaphragm 116, and a diaphragm driving. Unit 117, DRAM 118, and flash memory 119.

  The camera body 102 includes a camera controller 120, a body mount 121, a CMOS image sensor 122, a timing generator (TG) 123, an analog front end (AFE) 124, a liquid crystal monitor 125, a touch panel 104, and a release button 103. A camera-side operation unit 107, a power supply 126, a DRAM 127, a flash memory 128, a mechanical shutter 129, an acceleration sensor 130, an angular velocity sensor 131, a camera shake correction unit 132, a card slot 133, and a memory card 134. The camera controller 120 includes a camera shake control unit 135.

  In the present embodiment, a CMOS image sensor 122 is used as an image sensor. In addition, the angular velocity sensor 131 and the acceleration sensor 130 respectively detect the angular velocity and acceleration of camera shake that occurs in the camera body 102.

[1-2. Interchangeable lens configuration]
First, the configuration of the interchangeable lens 101 will be described.

  The lens system includes a focus lens 110 and a zoom lens 111, and collects light from the subject.

  The zoom lens 111 is driven by a zoom lens driving unit 114. The zoom lens driving unit 114 drives the zoom lens 111 according to the operation of the zoom ring 115 by the user.

  The focus lens 110 is driven by a focus lens driving unit 112. The focus lens driving unit 112 drives the focus lens 110 according to a user's operation of the focus ring 113 or a control signal from the camera controller 120 of the camera body 102.

  The diaphragm 116 adjusts the amount of light that passes through the lens system and enters the CMOS image sensor 122. The diaphragm 116 is driven by the diaphragm driver 117. The aperture driving unit 117 drives the aperture 116 in accordance with a control signal from the camera controller 120 of the camera body 102.

  The lens controller 108 controls the entire interchangeable lens 101. The lens controller 108 may be realized by a microcomputer or a hard-wired circuit. When the interchangeable lens 101 is attached to the camera body 102, the lens controller 108 reads out lens data stored in the flash memory 119 and transmits it to the camera controller 120.

  The DRAM 118 is used as a work memory for various controls by the lens controller 108. The flash memory 119 stores parameters and the like used for various controls by the lens controller 108.

[1-3. Configuration of camera body]
Next, the configuration of the camera body 102 will be described.

  The camera controller 120 controls the entire digital camera 100 such as the CMOS image sensor 122 in accordance with an instruction from the user's release button 103 or the camera side operation unit 107. The camera controller 120 notifies the timing generator 123 of the vertical synchronization signal. In parallel with this notification, the camera controller 120 generates an exposure synchronization signal based on the vertical synchronization signal. The camera controller 120 periodically notifies the lens controller 108 of the generated exposure synchronization signal via the body mount 121 and the lens mount 109. The camera controller 120 can write / read information to / from the DRAM 127 and the flash memory 128 as necessary. The camera controller 120 may be configured with a hard-wired electronic circuit or a microcomputer using a program.

  The DRAM 127 is used as a work memory for various controls by the camera controller 120. The flash memory 128 stores programs, parameters, and the like used for various controls by the camera controller 120.

  The CMOS image sensor 122 captures a subject image incident through the interchangeable lens 101 and generates image information. The generated image information is converted from analog format data to digital format data by the analog front end 124. The image information digitized by the analog front end 124 is subjected to various image processing by the camera controller 120. Examples of various image processing include gamma correction processing, white balance correction processing, scratch correction processing, YC conversion processing, electronic zoom processing, and JPEG compression processing, but are not limited thereto.

  Instead of the CMOS image sensor 122, for example, another imaging element such as an NMOS image sensor or a CCD image sensor may be used.

  The CMOS image sensor 122 operates at a timing controlled by the timing generator 123. The operation of the CMOS image sensor 122 includes a still image photographing operation, a through image photographing operation, a data transfer operation, an electronic front curtain reset operation, and an electronic front curtain operation. The through image is mainly a moving image, and the through image operation is an operation displayed on the liquid crystal monitor 125 in order to determine a composition for capturing a still image.

  The mechanical shutter 129 switches between blocking and passing of an optical signal incident on the CMOS image sensor 122 that is incident through the lens system. The mechanical shutter 129 is driven by a mechanical shutter driving unit (not shown). The mechanical shutter driving unit is composed of mechanical parts such as a motor and a spring, and drives the mechanical shutter 129 under the control of the camera controller 120. In short, the mechanical shutter 129 adjusts the amount of light hitting the CMOS image sensor 122 with time by opening and closing the mechanical shutter 129. The configuration of the mechanical shutter 129 will be described later.

  The body mount 121 is a connecting member for mechanically and electrically connecting the interchangeable lens 101 and the camera body 102 together with the lens mount 109 included in the interchangeable lens 101. When the interchangeable lens 101 and the camera body 102 are mechanically and electrically connected, the lens controller 108 and the camera controller 120 can communicate with each other. The body mount 121 notifies the lens controller 108 of the exposure synchronization signal and other control signals received from the camera controller 120 via the lens mount 109. The body mount 121 notifies the camera controller 120 of a signal received from the lens controller 108 via the lens mount 109.

  The release button 103 receives a user operation. The release button 103 can be operated in two steps, half-press and full-press. When the user presses release button 103 halfway, camera controller 120 controls to execute an autofocus operation. When the user fully presses the release button 103, the camera controller 120 generates an image according to the timing of the full press operation, and controls the generated image to be stored in the memory card 134.

  The camera side operation unit 107 is a general term for operation members including the center button 105 and the cross button 106, and includes a switch for switching between MF (Manual Focus) / AF (Auto Focus). When the camera side operation unit 107 receives an operation by the user, the camera controller 120 performs control corresponding to the operation instruction content.

  The CMOS image sensor 122 can be moved in the vertical direction, the horizontal direction, and the rotation direction by the camera shake correction unit 132. Details of the camera shake correction unit 132 will be described later.

  The acceleration sensor 130 is a sensor that detects the acceleration of the camera body 102. The acceleration sensor 130 detects the movement of the camera body 102 for a predetermined time, and outputs the detected acceleration to the camera shake control unit 135 in the camera controller 120. The acceleration sensor 130 is preferably a triaxial acceleration sensor.

  The angular velocity sensor 131 is a sensor that detects the angular velocity of the camera body 102. The angular velocity sensor 131 detects the movement of the camera body 102 for a predetermined time and outputs the angular velocity to the camera shake control unit 135. The camera shake control unit 135 generates a camera shake correction signal based on the signal obtained from the angular velocity sensor 131. By driving the CMOS image sensor 122 via the camera shake correction unit 132 in a direction to cancel camera shake generated in the digital camera 100 based on the camera shake correction signal, an image without camera shake can be taken.

  The camera shake correction signal created by the camera shake control unit 135 may be created not only from the angular velocity sensor 131 but also in combination with the signal from the acceleration sensor 130 in a shooting scene where translational shaking occurs.

[2-1. Camera controller control]
FIG. 4 is a timing chart showing the operation of the camera controller 120 in the first embodiment.

  When the power source 126 of the camera body 102 is turned on by the user, the camera controller 120 performs standby control. In standby control, the camera controller 120 displays image data obtained by the CMOS image sensor 122 on the liquid crystal monitor 125 as a through image. Details of the standby control will be described later.

  When the release button is fully pressed by the user, the camera controller 120 performs exposure control. The camera controller 120 realizes an electronic front curtain shutter by controlling the CMOS image sensor 122 and the mechanical shutter 129 in exposure control. The camera controller 120 reads image data of a still image while the CMOS image sensor 122 is shielded by the curtain of the mechanical shutter 129. When the reading of the image data is completed, the camera controller 120 moves the curtain of the mechanical shutter 129 to an open position where the CMOS image sensor 122 is not shielded. Details of the exposure control will be described later.

  When the photographing operation is completed, the camera controller 120 returns to standby control. Thereafter, when the power of the camera body 102 is turned off by the user, the camera controller 120 stops supplying power to the camera body 102.

[2-2. Exposure control]
FIG. 5 is a flowchart showing exposure control of the camera controller 120 in the first embodiment.
The camera controller 120 controls the CMOS image sensor 122 and executes an electronic front curtain as a front curtain. Thereafter, the camera controller 120 controls the mechanical shutter 129 and executes it as the rear curtain. Under this control, a photographing operation is executed.

  Here, the camera controller 120 performs the following adjustment in order to make the locus of the electronic front curtain more approximate to the locus of the mechanical shutter 129 as the rear curtain.

  The speed of the scanning pattern of the electronic front curtain is adjusted for each line. For example, the scanning speed to the next line increases from the start line to the end line. This is because the speed of the mechanical shutter 129 gradually increases at the beginning and end of closing.

  (Step T1) First, when the user fully presses the release button, the camera controller 120 adjusts the scanning pattern of the electronic front curtain in consideration of lens characteristics and photographing conditions, and the CMOS image sensor 122. The electronic front curtain is controlled, that is, the electronic front curtain is reset.

  (Step T2) Next, the camera controller 120 waits for the shutter speed after the start of the electronic front curtain reset.

  (Step T3) The curtain of the mechanical shutter 129 is driven in the closing direction.

  (Step T4) Thereafter, the camera controller 120 reads out still image data from the CMOS image sensor 122.

  (Step T5) Then, the camera controller 120 drives the curtain of the mechanical shutter 129 in the opening direction.

[2-3. Structure of camera shake correction in the body]
6 is a schematic diagram of the camera shake correction unit 132 and the CMOS image sensor 122 according to the first embodiment, FIG. 7 is a 7-7 direction view of the camera shake correction unit 132 in FIG. 6, and FIG. 8 is a camera shake correction unit in FIG. FIG. 8 is a view in the 8-8 direction.

  The camera shake correction unit 132 is in contact with the CMOS image sensor 122, and the CMOS image sensor 122 moves in conjunction with the movement of the camera shake correction unit 132. As shown in FIG. 7, the camera shake correction unit 132 includes a coil and a sensor on a surface opposite to the surface with which the CMOS image sensor 122 is in contact. Moreover, as shown in FIG. 8, a magnet group is arrange | positioned in the position facing the coil and sensor of FIG.

  As illustrated in FIG. 7, the camera shake correction unit 132 includes X direction coils 301 and 302 and a Y direction coil 303, and includes X direction position sensors 304 and 305 and a Y direction position sensor 306 on the back side of the CMOS image sensor 122. Further, as shown in FIG. 8, X-direction drive magnet units 307 and 308, Y-direction drive magnet units 309, X-direction position detection magnet units 310 and 311, and Y-direction position detection magnet units 312 are included.

  The X direction coil 301 and the X direction driving magnet unit 307 are arranged to face each other to form a voice coil motor, and the X direction coil 302 and the X direction driving magnet unit 308 are arranged to face each other to form a voice coil motor. The Y-direction coil 303 and the Y-direction driving magnet unit 309 are arranged to face each other to form a voice coil motor. As described above, the voice coil motor has two channels arranged on the X-axis side and one channel arranged on the Y-axis side.

  A position sensor is formed by the X direction position detecting magnet units 310 and 311 and the Y direction position detecting magnet unit 312. As described above, the position sensor has two channels arranged on the X-axis side and one channel arranged on the Y-axis side.

  Here, the reason why the three voice coil motors and the position sensors are provided is to correct the shake in the θ direction in addition to the X direction and the Y direction. Accordingly, the angular velocity sensor 131 also includes three axes in the X direction, the Y direction, and the θ direction.

  FIG. 9 is a diagram illustrating a movable range of the camera shake correction unit 132 according to the first embodiment. As shown in FIG. 9, the camera shake correction unit 132 is movable in the θ direction in addition to the X direction and the Y direction.

  In this embodiment, the voice coil motor and the position sensor are arranged in two channels on the X-axis side and one channel on the Y-axis side, but conversely, one channel is arranged on the X-axis side and two on the Y-axis side. Channel arrangement may be used, and the degree of freedom of arrangement is not limited to this.

The camera shake correction unit 132 has been described as having a movable range in the X direction, the Y direction, and the θ direction. However, only two axes in the X direction and the Y direction, or only one of the X direction, the Y direction, and the θ direction is movable. It does not matter as a range.
[2-4. [Problems when using in-body image stabilization and electronic front curtain shutter]
Here, a problem in the case where the in-body camera shake correction and the electronic front curtain shutter are used together will be described with reference to FIGS.

  FIG. 10 is a diagram illustrating an example of a trajectory curve of the electronic front curtain and the mechanical rear curtain, and FIG. 11 is a diagram illustrating another example of a trajectory curve of the electronic front curtain and the mechanical rear curtain.

  In-body camera shake correction has a camera shake prevention mode in which an operation for canceling camera shake is performed in accordance with the output of a camera shake detection signal from a through image. When the camera shake prevention mode is on, the position of the image sensor moves according to the output of the camera shake detection signal. In a situation where the position of the image sensor is moving, exposure control is started by the user fully pressing the release button 103, and the electronic front curtain and the mechanical rear curtain travel according to a predetermined shutter speed, Exposure control is completed.

  Since the electronic front curtain shutter is composed of an electronic front curtain and a mechanical rear curtain, it is important for the exposure control how accurately the electronic front curtain reset can be controlled with respect to the mechanical characteristic change of the mechanical rear curtain.

  Therefore, in the electronic front curtain shutter, the reset timing of the electronic front curtain reset is adjusted according to the locus of the mechanical rear curtain, and the reset scanning timing for each line of the CMOS image sensor 122 is adjusted so that the exposure time is constant. To do.

  In FIG. 10, trajectory curves of the electronic front curtain and the mechanical rear curtain are shown, with the horizontal axis indicating time and the vertical axis indicating the position of the shutter. The curve of the electronic front curtain is shown in time before the curve of the mechanical rear curtain. The interval between the two trajectory curves represents the exposure time.

  In FIG. 10, the interval between the locus curves of the electronic front curtain (exposure start) and the mechanical rear curtain (exposure end) is constant at the interval P1 from the start line S1 to the end line E1. Since this is constant above and below the CMOS image sensor 122, there is no exposure unevenness above and below the CMOS image sensor 122. The electronic front curtain reset start position when the CMOS image sensor 122 is adjusted so that the distance between the locus curves of the electronic front curtain and the mechanical rear curtain is constant as shown in FIG. .

  However, in the case where the camera shake correction in the body and the electronic front curtain shutter are used together, the position of the CMOS image sensor 122 moves in the Y direction from the initial position according to the magnitude of the camera shake before the electronic front curtain reset. There may be.

  FIG. 11 shows the trajectory curves of the electronic front curtain and the mechanical rear curtain when the CMOS image sensor 122 is moving downward. In FIG. 11, the horizontal axis indicates time, and the vertical axis indicates the position of the shutter. The curve of the electronic front curtain is shown in time before the curve of the mechanical rear curtain. The interval between the two trajectory curves represents the exposure time.

  In FIG. 11, even if the CMOS image sensor 122 has moved downward, exposure control is performed assuming that the CMOS image sensor 122 is in the initial position, so the start line S1 is shifted to the start line S2 and the end line E1. Shifts to the end line E2.

  The interval between the trajectory curve of the electronic front curtain and the mechanical rear curtain from the start line S2 to the end line E2 gradually increases from the start line S2 to the end line E2, with the interval P2 <interval P3 <interval P4. For this reason, the interval between the trajectory curves is different between the upper and lower sides of the CMOS image sensor 122, and uneven exposure occurs.

  FIG. 12 is a diagram for explaining the photographing operation when the CMOS image sensor 122 is in the initial position. FIG. 12 shows a state in which the CMOS image sensor 122 and the mechanical shutter 129 are observed along the optical axis direction from the optical system side, and the CMOS after the start of shooting by the user fully pressing the release button 103 is shown. A state in which the traveling of the electronic front curtain 1201 performed by the image sensor 122 and the traveling of the mechanical rear curtain 1202 of the mechanical shutter 129 are in the middle is shown. The arrows indicate the traveling direction of the electronic front curtain 1201 and the traveling direction of the mechanical rear curtain 1202.

  FIG. 12 shows a state in which the electronic front curtain 1201 and the mechanical rear curtain 1202 shield a part of the area of the CMOS image sensor 122. A region 1205 between the end 1203 of the electronic front curtain 1201 and the end 1204 of the mechanical rear curtain 1202 is a region that is not shielded by either the electronic front curtain 1201 or the mechanical rear curtain 1202. That is, the region 1205 is a charge accumulation region where charge accumulation by exposure is performed in the CMOS image sensor 122. In FIG. 12, since the CMOS image sensor 122 is in the initial position, the right and left accumulation sections L1 and L2 are equal in the region 1205. Therefore, there is no exposure unevenness on the left and right of the CMOS image sensor 122.

  FIG. 13 is a diagram for explaining a photographing operation when the CMOS image sensor 122 is not in the initial position.

  FIG. 13 shows a state in which the CMOS image sensor 122 and the mechanical shutter 129 are observed along the optical axis direction from the optical system side, and the CMOS after the start of shooting by the user fully pressing the release button 103 is shown. A state in which the traveling of the electronic front curtain 1201 performed by the image sensor 122 and the traveling of the mechanical rear curtain 1202 of the mechanical shutter 129 are in the middle is shown. The arrows indicate the traveling direction of the electronic front curtain 1201 and the traveling direction of the mechanical rear curtain 1202.

  FIG. 13 shows a state in which the electronic front curtain 1201 and the mechanical rear curtain 1202 shield a part of the area of the CMOS image sensor 122. A region 1205 between the end 1203 of the electronic front curtain 1201 and the end 1204 of the mechanical rear curtain 1202 is a region that is not shielded by either the electronic front curtain 1201 or the mechanical rear curtain 1202. That is, the region 1205 is a charge accumulation region where charge accumulation by exposure is performed in the CMOS image sensor 122.

In FIG. 13, the rotation correction is performed by the camera shake correction in the body, and the CMOS image sensor 122 is rotated. The angle of the CMOS image sensor 122 changes from the initial position in accordance with the magnitude of the rotational hand shake. When the CMOS image sensor 122 is rotating and the same exposure control is performed as when the CMOS image sensor 122 is at the initial position, the left and right accumulation sections L1 and L2 of the CMOS image sensor 122 are different. Therefore, exposure unevenness occurs on the left and right of the CMOS image sensor 122.
[2-5. Operation of electronic front curtain shutter]
Therefore, in the first embodiment, when the in-body camera shake correction and the electronic front curtain shutter are used together, the exposure control is performed after the CMOS image sensor 122 is moved to the initial position.

  FIG. 14 is a flowchart showing the photographing operation in the first embodiment. A photographing operation when the CMOS image sensor 122 is at a position shifted in the Y direction from the initial position will be described.

  (Step S1401) The release button 103 is fully pressed by the user, and the photographing operation is started.

  (Step S1402) The camera controller 120 acquires information from the camera shake correction unit 132, and determines whether or not the camera shake prevention mode is on. If the image stabilization mode is on (Yes), the process proceeds to step S1403. If the image stabilization mode is not on (No), the process proceeds to step S1407.

  (Step S1403) The camera controller 120 determines whether or not a through image is being operated. If the through image is being operated (Yes), the process proceeds to step S1404. If the through image is not being operated (No), the process proceeds to step S1407.

  (Step S1404) The camera shake control unit 135 acquires position information in the Y direction for camera shake correction from the angular velocity sensor 131. Based on the acquired position information, the camera shake control unit 135 determines whether the amount of movement of the CMOS image sensor 122 in the Y direction is within a specified value from the initial position. Here, the specified value is, for example, the unevenness of the exposure time among the exposure time tolerance, which is the performance of the shutter mechanism used in the camera for photography of “Japanese Industrial Standard: JISB7091-1992 Camera Shutter”. Since the reference value of the exposure time is shorter than 1/125 and is defined as 0.6 EV or less, it is set to 0.6 EV. More specifically, the value of the upper and lower exposure unevenness of the CMOS image sensor 122 is set within a specified value of 0.6 EV.

FIG. 15 is a diagram for explaining the measurement of the upper and lower exposure unevenness of the CMOS image sensor 122.
For the upper and lower exposure unevenness, the exposure of the first region 122a that is the upper part of the CMOS image sensor 122 and the second region 122b that is the lower part of the CMOS image sensor 122 is measured, and the difference is taken as the exposure unevenness. The first region 122a is a region for several pixels from the top of the CMOS image sensor 122, and the second region 122b is a region for several pixels from the bottom of the CMOS image sensor 122. The exposure is measured by measuring the exposure of each pixel in the first region 122a, taking the average value as the exposure of the first region 122a, measuring the exposure of each pixel in the second region 122b, and measuring the average value of the second region 122b. Exposure.

  In addition, regarding the measurement of the upper and lower exposure unevenness of the CMOS image sensor 122, the determination may be made in any state of the RAW state of the CMOS image sensor 122 and the state after correction such as gamma correction.

  Further, the specified value may be relaxed as the shutter speed becomes longer.

  If the camera shake control unit 135 determines that the amount of movement of the CMOS image sensor 122 is within the specified value (in the case of No), the process proceeds to step S1407, and if the amount of movement of the CMOS image sensor 122 is determined to be greater than the specified value ( In the case of Yes), the process proceeds to step S1405.

  (Step S1405) The camera controller 120 controls the camera shake correction unit 132 to reset, and moves the CMOS image sensor 122 along the Y-axis direction. That is, the camera controller 120 causes the camera shake correction unit 132 to move the CMOS image sensor 122 in the scanning direction of the electronic front curtain of the CMOS image sensor 122.

  (Step S1406) The camera shake controller 135 determines whether or not the position of the CMOS image sensor 122 is within a specified value from the initial position. If it is within the specified value (in the case of Yes), the movement of the CMOS image sensor 122 is stopped, and the process proceeds to step S1407. If the position of the CMOS image sensor 122 is not within the specified value (in the case of No), step S1405 is performed. Return to.

  (Step S1407) The exposure control described in FIG. 5 is performed.

In the flowchart, the photographing operation in the case where the CMOS image sensor 122 is in a position shifted in the Y direction from the initial position has been described. However, the case where the CMOS image sensor 122 is in a position shifted in the rotational direction from the initial position is also described. The same operation is performed.
[3. effect]
As described above, in the present embodiment, the imaging apparatus includes a camera shake detection unit that detects camera shake, an image sensor that captures a subject image, and a camera shake correction unit that moves the image sensor in a plane perpendicular to the optical axis. A camera shake correction signal is generated from an electronic front curtain that resets the amount of charge stored in the image sensor, a mechanical shutter that switches between shielding and passing the subject image collected on the image sensor, and a camera shake detected by the camera shake detection unit. A camera shake control unit that controls the correction unit. When receiving a shooting instruction, the camera shake control unit moves the image sensor to a predetermined position and then controls the electronic front curtain to operate.

  As a result, it is possible to suppress the occurrence of uneven exposure when the in-body camera shake correction and the electronic front curtain shutter are used in combination.

(Other embodiments)
As described above, the first embodiment has been described as an example of the present disclosure. However, the present invention is not limited to this, and the present invention can be applied to embodiments in which changes, replacements, additions, omissions, etc. are made as appropriate.

  Therefore, other embodiments will be described below.

  In the first embodiment, the electronic front curtain shutter has been described. However, in an imaging apparatus having a mechanical front curtain, an electronic front curtain reset may be used instead of the mechanical front curtain.

  In the first embodiment, a CMOS image sensor is used as the image sensor. However, another image sensor having an electronic front curtain reset may be used.

  In the first embodiment, the camera shake correction in the body that is movable in three axes in the Y-axis direction, the X-axis direction, and the rotation axis direction has been described. However, in-body camera shake correction that is biaxially movable in the Y-axis direction and the X-axis direction may be performed, and the movable axis may be limited by drive control only in the rotation axis direction.

  In the first embodiment, the angular velocity sensor is used to detect camera shake. However, an acceleration sensor may be used for camera shake detection, another sensor such as an image sensor, or a plurality of sensors may be used in combination.

  In the first embodiment, the voice coil motor is used as the camera shake correction actuator. However, another actuator such as an ultrasonic motor or a stepping motor may be used.

  The present disclosure can be applied to an imaging apparatus including in-body camera shake correction and an electronic front curtain shutter such as a digital camera, a movie, and a digital single lens camera.

DESCRIPTION OF SYMBOLS 100 Digital camera 101 Interchangeable lens 102 Camera body 103 Release button 104 Touch panel 105 Center button 106 Cross button 107 Camera side operation part 108 Lens controller 109 Lens mount 110 Focus lens 111 Zoom lens 112 Focus lens drive part 113 Focus ring 114 Zoom lens drive part 115 Zoom Ring 116 Aperture 117 Aperture Drive Unit 118 DRAM
119 Flash memory 120 Camera controller 121 Body mount 122 CMOS image sensor 122a First area 122b Second area 123 Timing generator 124 Analog front end 125 Liquid crystal monitor 126 Power supply 127 DRAM
128 Flash memory 129 Mechanical shutter 130 Acceleration sensor 131 Angular velocity sensor 132 Camera shake correction unit 133 Card slot 134 Memory card 135 Camera shake control unit 301, 302 X direction coil 303 Y direction coil 304, 305 X direction position sensor 306 Y direction position sensor 307, 308 X-direction driving magnet section 309 Y-direction driving magnet section 310, 311 X-direction position detection magnet section 312 Y-direction position detection magnet section 1201 Electronic front curtain 1202 Mechanical rear curtain 1203, 1204 End section 1205 Area

Claims (6)

A camera shake detection unit for detecting camera shake;
An image sensor for capturing a subject image;
A camera shake correction unit that moves the image sensor in a plane perpendicular to the optical axis;
An electronic front curtain for resetting the accumulated charge amount of the image sensor;
A mechanical shutter that switches between shielding or passing of the subject image condensed on the image sensor;
A camera shake control unit that creates a camera shake correction signal and controls the camera shake correction unit from the camera shake detected by the camera shake detection unit;
The camera shake correction unit moves the image sensor in order to cancel the camera shake before a shooting instruction,
The hand shake control section controls the image sensor and receiving the photographing instruction has been moved before the photographing instructed to move, when the position of the imaging device is within the first distance from Jo Tokoro position, An imaging apparatus that controls the electronic front curtain to operate. The hand shake control section, an imaging instruction to receive, controls to move the image pickup device along a scan direction of the electronic front curtain, the imaging apparatus according to claim 1. The imaging apparatus according to claim 1, wherein the camera shake control unit controls to move the image sensor in a rotation direction of the image sensor in response to an imaging instruction.   The imaging apparatus according to claim 1, wherein the predetermined position is an initial position of the imaging element. 2. The imaging apparatus according to claim 1, wherein the first distance is a position where an uneven exposure on the top and bottom of the imaging element is 0.6 EV from an initial position of the imaging element. The camera shake control unit receives a shooting instruction,
If the imaging device is not within the first distance, and controls to move the image pickup element within the first distance, if the imaging device is within the first distance, moving the imaging device Do not control,
The imaging device according to claim 1.

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